function [v12] = V12(yh,yf1,v1,L1,M)
%yh为蓝方无人机y值，yf1为F1的y值，M为区域宽度（AB）距离
y12=yh-yf1;
if(abs(y12)>=L1)
    v12=sign(y12)*(-v1/M*(abs(y12)-M));
else
    v12=sign(y12)*v1/L1*abs(y12);
end

